A modified version of the base of the third hand for soldering. Please download the other parts there!

The part requires up to 6 30x10x3mm magnets and up to 16 M8 nuts. Pause the prints just before the cavities are covered up to embed the magnets and nuts within the part.

I realized after printing the part that the solid space between the top of the nuts and the top surface was a bit short, leading to a bad top surface finish (as can be seen in teh second image). I added some more height to the part, which should hopefully mitigate that.